The answer is 'A. consequence'
ENVIRONMENT
There are many theories discussing how genetics and upbringing shape a person’s personality throughout his life. Ryan’s interaction with his environment and the experiences he had throughout his life shapes his personality. Openness, conscientiousness, extraversion, agreeableness and neuroticism are the five traits that influence how he participates with his surroundings.
Theorists believed that early life experiences have the maximum impact in a person’s personality. However, they also argued that new life experiences, temperament, the kind of social roles or simply growing older can change an individual’s personality over time.
This can help in different ways, one being that words you may have thought you have spelt write may be wrong or the context, tone or how the words read may not be very good or easy to understand. This will also help to have clean eyes on the work that haven't seen it before, these can offer advice and judgement on things tht should or shouldn't be in there,
My guess would be that they increase the activity of the nervous system. I hope this helps! :)